Absolute photoionization cross-sections of some combustion intermediates

Near-threshold absolute photoionization and dissociative photoionization cross-sections for photon energies from 9.7 to 11.75 eV are presented for 30 combustion intermediates including hydrocarbons, oxygenates and nitrogenous compounds (trans-2-butene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, trans-2-hexene, 1-hexene, allene, 1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, 3-methyl-1,2-butadiene, 1,5-hexadiene, isobutane, methylcyclohexane, furan, 2,3-dihydrofuran, 2,5-dihydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, n-butanal, isobutanal, 2-butenal, 3-methyl-2-butenal, ketene, allyl alcohol, methyl vinyl ketone, dimethoxymethane, methylamine, ethylamine, piperidine). Because allene is one of the most important intermediates in hydrocarbon combustion and pyrolysis processes, very accurate cross-sections for allene are desired to enable the measurement of its mole fractions in flames and to determine relative concentration ratios of allene to its isomer propyne. The cross-sections for allene have thus been re-measured with high precision using an apparatus of improved signal/noise ratio. Furthermore, these allene cross-sections yield accurate previously unmeasured cross-sections for ketene, another key combustion intermediate. (C) 2011 Elsevier B.V. All rights reserved.